European Journal of Organic Chemistry

Cover image for Vol. 2014 Issue 30

Early View (Online Version of Record published before inclusion in an issue)

Editor: Haymo Ross, Deputy Editor: Susan Wilkinson

Impact Factor: 3.154

ISI Journal Citation Reports © Ranking: 2013: 14/58 (Chemistry Organic)

Online ISSN: 1099-0690

Associated Title(s): Advanced Synthesis & Catalysis, Asian Journal of Organic Chemistry

VIEW

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  1. Microreviews

    1. Multicomponent Reactions

      The Ugi–Smiles and Passerini–Smiles Couplings: A Story About Phenols in Isocyanide-Based Multicomponent Reactions

      Laurent El Kaïm and Laurence Grimaud

      Article first published online: 19 OCT 2014 | DOI: 10.1002/ejoc.201402783

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      The Ugi–Smiles and Passerini–Smiles couplings are isocyanide-based multicomponent reactions involving phenols and each featuring a Smiles rearrangement as a key step of the mechanism. Their scope, mechanistic studies, and the use of these couplings for a variety of routes to fused aromatic systems are reviewed here.

  2. Short Communications

    1. Conjugated Chirons

      Transformation of Glycals into α,β,γ,δ-Conjugated Chirons under Metal-Free Conditions

      Tatina Madhubabu, Syed Khalid Yousuf, Anil Kumar Kusunuru and Debaraj Mukherjee

      Article first published online: 19 OCT 2014 | DOI: 10.1002/ejoc.201403041

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      A diastereoselective, metal-free, one-pot domino synthetic strategy is developed for the transformation of glycals into new chiral scaffolds. Optimization of the reaction conditions to exclude normal Ferrier products, characterization of the new entities, and a plausible mechanism are presented (TMSOTf: trimethylsilyl trifluoromethanesulfonate).

    2. Trifluoromethylthiolation

      An Improved Protocol for the Synthesis of α-Trifluoromethylthio-Substituted Ketones by Copper-Mediated Trifluoromethylthiolation of α-Bromo Ketones

      Yangjie Huang, Xing He, Haohong Li and Zhiqiang Weng

      Article first published online: 19 OCT 2014 | DOI: 10.1002/ejoc.201403221

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      An improved protocol for the copper-mediated trifluoromethylthiolation of α-bromo ketones by using (bpy)Cu(SCF3) (bpy = 2,2′-bipyridyl) to afford the corresponding α-trifluoromethylthio-substituted ketones in good to excellent yields is presented. The procedure tolerates electron-withdrawing and electron-donating groups on the aromatic rings.

  3. Full Papers

    1. Nitrogen Heterocycles

      Mechanistic Study of a Complementary Reaction System that Easily Affords Quinazoline and Perimidine Derivatives

      Zerong Daniel Wang, Joshua Eilander, Motoko Yoshida and Tianzhi Wang

      Article first published online: 15 OCT 2014 | DOI: 10.1002/ejoc.201402854

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      The mechanism of a novel reaction to form substituted quinazoline and perimidine derivatives has been elucidated. This reaction involves the thermal decomposition of thiourea to form carbodiimide and H2S, the former couples with 2-aminobenzophenone to form 4-phenylquinazolin-2(1H)-imine intermediate, which is then reduced and converted into 4-phenylquinazoline.

  4. Short Communications

    1. Kinetics

      Unusual Reaction Constant for Hydride Transfer from a Carbanion to 9-Arylxanthyliums

      Fengrui Liu and Xiaoqing Zhu

      Article first published online: 15 OCT 2014 | DOI: 10.1002/ejoc.201403023

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      An unusual reaction constant obtained from the kinetics for hydride transfer from a carbanion to 9-arylxanthyliums is obtained. The results are in contrast to thermodynamics analysis results for simple hydride-transfer reactions and indicate that this reaction is no longer a simple hydride-transfer reaction. An “intermediate” is also found during the reaction, and a possible structure is proposed.

    2. Organocatalysis

      Cinchona-Derived Picolinamides: Effective Organocatalysts for Stereoselective Imine Hydrosilylation

      Pedro C. Barrulas, Andrea Genoni, Maurizio Benaglia and Anthony J. Burke

      Article first published online: 15 OCT 2014 | DOI: 10.1002/ejoc.201403180

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      Cinchona derivatives for the successful enantioselective addition of trichlorosilane to ketimines are developed. Excellent yields with good to high enantioselectivities (up to 91 %) are obtained in the reduction of differently substituted substrates. Remarkably high turnover frequencies for imine hydrosilylation are observed at a catalyst loading of only 1 mol-%.

  5. Full Papers

    1. Heterocyclization

      Heterocycle-to-Heterocycle Route to Quinoline-4-amines: Reductive Heterocyclization of 3-(2-Nitrophenyl)isoxazoles

      Keith C. Coffman, Vy Duong, Alex L. Bagdasarian, James C. Fettinger, Makhluf J. Haddadin and Mark J. Kurth

      Article first published online: 15 OCT 2014 | DOI: 10.1002/ejoc.201403065

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      A variety of quinoline-4-amines were synthesized from 3-(2-nitrophenyl)isoxazoles via reductive heterocyclization with Zn0 or Fe0 and HOAc; starting isoxazoles were synthesized from readily available starting materials. A brief survey of tolerated functional groups was performed and a few examples of 10-amino-3,4-dihydrobenzo[b][1,6]naphthyridin-1(2H)-ones were also synthesized and diversified.

  6. Short Communications

    1. Transfer Hydrogenation

      Photodriven Transfer Hydrogenation of Olefins

      Dasheng Leow, Ying-Ho Chen, Tzu-Hang Hung, Ying Su and Yi-Zhen Lin

      Article first published online: 15 OCT 2014 | DOI: 10.1002/ejoc.201403021

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      An improved practical method for the photodriven diimide reduction of olefins is reported. This catalyst-free procedure proceeds at ambient temperature, utilizes air as the oxidant and a lower hydrazine loading, and produces inert nitrogen gas as the sole byproduct. Several functional groups are tolerated and the reaction can be chemoselective. CFL = compact fluorescent light.

    2. C–H Activation

      Functionalization of the Benzylic C–H Bonds in Azaarenes by Cobalt-Catalyzed 1,4-Addition to Enones

      Zaini Jamal, Yong-Chua Teo and Ling-Keong Wong

      Article first published online: 15 OCT 2014 | DOI: 10.1002/ejoc.201403203

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      Functionalization of the C(sp3)–H bonds in azaarenes catalyzed by CoCl2 as an inexpensive Lewis acid catalyst is reported. Enones are demonstrated to be good C=C electrophilic acceptors for the construction of various azaarene-containing 1,4-addition products in yields up to 95 %.

  7. Full Papers

    1. Cyclic Rearrangement

      Facile Redox Interconversion of 6,11-Diphenyldibenzo[b,f][1,4]diazocine and 2-(2-Aminophenyl)-1,3-diphenylisoindole: Reversible SET Ring Contraction and Expansion Processes

      John J. Eisch, Wei Liu, Lisheng Zhu and Arnold L. Rheingold

      Article first published online: 14 OCT 2014 | DOI: 10.1002/ejoc.201403101

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      Our attempt to form the aromatic 6,11-diphenyldibenzo[b,f]5,12-dihydro[1,4]diazocine by treating 6,11-diphenyldibenzo[b,f][1,4]diazocine with Na and then water led instead to 2-(2-aminophenyl)-1,3-diphenylisoindole. Other reductants for this reaction were o-diaminobenzene (o-DAB), titanium(II) salts and HI; the reverse reaction was caused by O2 or DDQ.

    2. Catalytic C–N Coupling

      Concise Synthesis of Vesnarinone and Its Analogues by Using Pd-Catalyzed C–N Bond-Forming Reactions

      Yi Yang See, Tuan Thanh Dang, Anqi Chen and Abdul Majeed Seayad

      Article first published online: 14 OCT 2014 | DOI: 10.1002/ejoc.201403054

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      An efficient and concise synthesis of vesnarinone was achieved in three steps by using palladium-catalyzed C–N bond-forming reactions, which included the Buchwald–Hartwig amination and an aminocarbonylation reaction. High overall yields were obtained by using this strategy for the preparation of several vesnarinone analogues.

    3. Configuration Determination

      Chiroptical Signatures of Planar and Central Chirality in [2]Paracyclo[2](5,8)quinolinophane Derivatives

      Giuseppe Mazzeo, Giovanna Longhi, Sergio Abbate, Federica Buonerba and Renzo Ruzziconi

      Article first published online: 14 OCT 2014 | DOI: 10.1002/ejoc.201402945

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      Quinolinophane derivatives possessing both planar and central chirality are investigated by experimental and computational chiroptical methods. Vibrational circular dichroism defines unequivocally planar chirality and optical rotation measurements provide an excellent indication of central chirality.

    4. Lewis Acid Catalysis

      Access to Polycyclic Derivatives by Triflate-Catalyzed Intramolecular Hydroarylation

      Bastien Cacciuttolo, Sophie Poulain-Martini, Fabien Fontaine-Vive, Mahmoud Ali Hussein Abdo, Hussein El-Kashef and Elisabet Duñach

      Article first published online: 13 OCT 2014 | DOI: 10.1002/ejoc.201402972

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      Nonactivated aromatic compounds bearing side-chain olefin substituents were cyclised into polycyclic compounds in good-to-excellent yields under In(OTf)3 (OTf = trifluoromethanesulfonate) and Bi(OTf)3 catalysis. This intramolecular cycloisomerisation leads to the synthesis of indane, tetralin or benzosuberan derivatives and allows sequential and tandem polycyclisations in one step.

    5. Micelles

      Micellar Polyaromatic Capsules: Enhanced Emissive Properties through Shell-Functionalization

      Kei Kondo, Akira Suzuki, Munetaka Akita and Michito Yoshizawa

      Article first published online: 10 OCT 2014 | DOI: 10.1002/ejoc.201403136

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      Functionalization of the polyaromatic shell of a micelle-like molecular capsule was accomplished by simple functionalization of the amphiphilic subunits. The shell-functionalization drastically enhances the host and host–guest emissive properties.

    6. Ketone α-Arylation

      Di-tert-butylneopentylphosphine (DTBNpP): An Efficient Ligand in the Palladium-Catalyzed α-Arylation of Ketones

      Steven M. Raders, Jessica M. Jones, Jeffrey G. Semmes, Steven P. Kelley, Robin D. Rogers and Kevin H. Shaughnessy

      Article first published online: 10 OCT 2014 | DOI: 10.1002/ejoc.201402474

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      Ketone α-arylation with aryl bromides and chlorides using di-(tert-butyl)neopentylphosphine (DTBNpP) in combination with palladium is described. This catalyst system provides an efficient route to benzofurans through the condensation of 2-bromophenols with ketones.

  8. Short Communications

    1. Amino Acids

      Organocatalyzed Asymmetric 1,4-Addition of Azlactones to α,β-Unsaturated Trichloromethyl Ketones: Synthesis of α,α-Disubstituted α-Amino Acid Derivatives

      Jinlong Zhang, Xihong Liu, Chongyang Wu, Panpan Zhang, Jianbo Chen and Rui Wang

      Article first published online: 9 OCT 2014 | DOI: 10.1002/ejoc.201403158

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      The first asymmetric 1,4-addition of azlactones to α,β-unsaturated trichloromethyl ketones by using cinchona alkaloid derived bifunctional thiourea catalysts is described. A series of α,α-disubstituted α-amino acid derivatives bearing a quaternary stereocenter at the α-position are obtained in high yields with excellent diastereo- and enantioselectivities (up to >20:1 dr and 99 % ee).

    2. Carboxylic Acid Conversion

      Acyloxyphosphonium versus Aminophosphonium Intermediates: Application to the Synthesis of N-Acylbenzotriazoles

      Chuthamat Duangkamol, Sirilak Wangngae, Mookda Pattarawarapan and Wong Phakhodee

      Article first published online: 9 OCT 2014 | DOI: 10.1002/ejoc.201403076

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      In synthesizing N-acylbenzotriazoles by using Ph3P/I2 as an acid activator, anhydride is exclusively generated upon adding Et3N to the presumed acyloxyphosphonium intermediate before treatment with 1H-benzotriazole (BtH). In the absence of base, benzotriazophosphonium iodide is predominantly formed, which rapidly reacts with carboxylate ions to afford N-acylbenzotriazoles in good to excellent yields.

    3. Natural Products

      Synthesis of β-Lapachone, a Potential Anticancer Agent from the Lapacho Tree

      Takeru Katoh, Hiromitsu Monma, Jun Wakasugi, Koichi Narita and Tadashi Katoh

      Article first published online: 9 OCT 2014 | DOI: 10.1002/ejoc.201403064

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      β-Lapachone is efficiently synthesized in four steps in 70 % overall yield starting from commercially inexpensive 1,4-naphthoquinone. The synthesis features the direct conversion of 2-prenyl-1,4-naphthoquinone into β-lapachone through an advantageous cyclization/hydration/oxidation cascade process.

  9. Microreviews

    1. Steroid Synthesis

      Asymmetric Assembly of Steroidal Tetracyclic Skeletons

      Preeti Gupta and Gautam Panda

      Article first published online: 9 OCT 2014 | DOI: 10.1002/ejoc.201402822

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      The review highlights recent advances in the enantioselective synthesis of carbocyclic steroidal skeletons. Various synthetic approaches based on the use of chiral starting materials, reagent-controlled asymmetric induction and asymmetric synthesis with the aid of chiral auxiliaries are discussed.

  10. Full Papers

    1. Arene Amination

      RhIII-Catalysed Hydrazine-Directed C(sp2)–H Amination of Phenidones with N-Alkyl-O-benzoyl-hydroxylamines

      Yu Xue, Zhoulong Fan, Xiaolong Jiang, Kui Wu, Meining Wang, Chunyong Ding, Qizheng Yao and Ao Zhang

      Article first published online: 9 OCT 2014 | DOI: 10.1002/ejoc.201402999

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      A RhIII-catalysed ortho C–H amination of phenidones under mild conditions at room temperature was developed using N-alkyl-O-benzoyl-hydroxylamines as aminating agents, and with a cyclic hydrazine moiety as a directing group, yields of up to 97 % and a high functional group tolerance were observed.

    2. Domino Reaction

      Iron-TEMPO-Catalyzed Domino Aerobic Alcohol Oxidation/Oxidative Cross-Dehydrogenative Coupling for the Synthesis of α-Keto Amides

      Surya Srinivas Kotha, Selvaraj Chandrasekar, Samrat Sahu and Govindasamy Sekar

      Article first published online: 9 OCT 2014 | DOI: 10.1002/ejoc.201402961

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      An iron-TEMPO-catalyzed (TEMPO = 2,2,6,6-tetramethyl-1-piperidinyloxy), aerobic process was developed to synthesize α-keto amides. This reaction proceeds through a domino alcohol oxidation/oxidative cross-dehydrogenative coupling sequence and uses 2-hydroxyacetophenones and amines as the starting materials.

    3. Addition Reactions

      Toward Bis C,C-Glycosyl Compounds and Anomeric γ-Glycoamino Acids through Michael Addition Reaction of Nitromethane on Z/E Push-Pull Sugar Olefins

      Mylène Richard, Anne-Sophie Felten, Claude Didierjean, Manuel Ruiz-Lopez, Yves Chapleur and Nadia Pellegrini-Moïse

      Article first published online: 8 OCT 2014 | DOI: 10.1002/ejoc.201402958

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      The Michael addition reaction of a nitronate anion at the anomeric center of push-pull sugar olefins gave a new and efficient access to bis C,C-glycosyl compounds that could be converted into optically pure anomeric γ-amino acids. A strong difference in the reactivity of the E and Z isomers of the exo-glycals was observed and was rationalized by quantum chemical calculations.

    4. Cross-Coupling

      Synthesis of Soai Type 2-Arylpyrimidine-5-carbaldehydes through Desulfurative Cross-Coupling with Arylboronic Acids

      Oleg V. Maltsev, Rodger Rausch, Zheng-Jun Quan and Lukas Hintermann

      Article first published online: 8 OCT 2014 | DOI: 10.1002/ejoc.201403133

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      2-Arylpyrimidine-5-carbaldehydes, which are of relevance as substrates in Soai's asymmetric autocatalysis, are prepared through Liebeskind–Srogl coupling of aryl boronic acids with 2-methylthiopyrimidine-5-carbaldehyde; the latter is obtained in a hydrolytic condensation of two symmetric amidinium salts.

    5. Heterocycle Synthesis

      Synthesis of 6-Substituted Phenanthridine Derivatives by Palladium-Catalysed Domino Suzuki–Miyaura/Aza-Michael Reactions

      Xiaobo Bao, Wei Yao, Qihua Zhu and Yungen Xu

      Article first published online: 8 OCT 2014 | DOI: 10.1002/ejoc.201402913

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      A domino reaction involving a palladium-catalysed Suzuki–Miyaura reaction followed by an intramolecular aza-Michael addition is presented. This allows the formation of a C–C bond and a C–N bond under mild conditions in one pot.

    6. Bioconjugate β-Lactams

      β-Lactam Bioconjugates Bearing Luminescent Platinum(II) Tags: Synthesis and Photophysical Characterization

      Roberto Soldati, Alessandro Aliprandi, Matteo Mauro, Luisa De Cola and Daria Giacomini

      Article first published online: 8 OCT 2014 | DOI: 10.1002/ejoc.201402740

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      New complexes based on a β-lactam unit and platinum metal ion were synthesized and the β-lactam conjugates showed interesting photophysical properties. The formation of aggregates, due to the square-planar geometry of the PtII species, leads to new excited states that allow excitation in the visible region.

  11. Microreviews

    1. Natural Product Synthesis

      Neocryptolepine (Cryprotackieine), A Unique Bioactive Natural Product: Isolation, Synthesis, and Profile of Its Biological Activity

      Andrea B. J. Bracca, Daniel A. Heredia, Enrique L. Larghi and Teodoro S. Kaufman

      Article first published online: 6 OCT 2014 | DOI: 10.1002/ejoc.201402910

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      Neocryptolepine is an indoloquinoline alkaloid, isolated from Cryptolepis sanguinolenta. The isolation of the natural product and the numerous and different approaches directed towards its total synthesis, as well as its biological activity profile and spectroscopic studies, are discussed.

  12. Full Papers

    1. Polycyclic Structures

      Tribenzotriquinacenes that Bear Three Peripheral Pentaphenylphenyl Residues: Steric Crowding at a Bowl-Shaped Core

      Ehsan Ullah Mughal, Beate Neumann, Hans-Georg Stammler and Dietmar Kuck

      Article first published online: 6 OCT 2014 | DOI: 10.1002/ejoc.201402995

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      C3- and C1-symmetrical tribenzotriquinacene-based tris-tolanes were synthesized and found to be separable, in contrast to TBTQ trialdehydes, triacetylenes and triiodo precursors. Both 2,6,10- and 2,6,11-tris-tolanes were converted into the tris-pentaphenylphenyl-TBTQ hydrocarbons, as shown for the C3-isomer. Attempts to generate warped TBTQ-centered graphene cuttings from the C3 derivative failed.

    2. Bridged-Ring Systems

      Synthesis of Quinuclidines by Intramolecular Silver-Catalysed Amine Additions to Alkynes

      Arjen C. Breman, Andrea Ruiz-Olalla, Jan H. van Maarseveen, Steen Ingemann and Henk Hiemstra

      Article first published online: 6 OCT 2014 | DOI: 10.1002/ejoc.201403099

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      We report the synthesis of (enantiomerically pure) 2-alkylidenequinuclidines by an intramolecular hydroamination reaction catalysed by silver triflate. After cyclization to the appropriate quinuclidines, the cinchona alkaloids dihydroquinidine and dihydroquinine were obtained in a two-step procedure.

  13. Short Communications

    1. DNA Fluorescence

      Synthesis of a Photostable Energy-Transfer Pair for “DNA Traffic Lights”

      Peggy R. Bohländer and Hans-Achim Wagenknecht

      Article first published online: 6 OCT 2014 | DOI: 10.1002/ejoc.201403119

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      Slow photobleaching: A new cyano-substituted thiazole red derivative as a red emitter and a novel green fluorescent donor dye of the cyanine styryl type can be combined into an energy-transfer pair in DNA with excellent photostability, large wavelength shift, and good color contrast ratio.

  14. Full Papers

    1. Quinones

      Reactions of p-Quinols with Aldehydes and Imines: Stereoselective Access to Polyheterobicyclic and Tricyclic Systems

      Carolina García-García, María C. Redondo, María Ribagorda and M. Carmen Carreño

      Article first published online: 6 OCT 2014 | DOI: 10.1002/ejoc.201403114

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      Base-promoted reactions of p-quinols with aldehydes or sulfonyl imines enable direct access to dihydrobenzo[d][1,3]dioxolone or tetrahydrobenzo[d]oxazolone skeletons. A stereoselective synthesis of tricyclic systems was achieved by using sulfonyl imine and DABCO/LiClO4 in THF through a domino sequence of 1,2-addition, intramolecular aza-Michael and aza-Diels–Alder reactions.

    2. Carbocycle Synthesis

      Phase-Transfer-Catalyst-Mediated Domino Reaction of γ-Nitro Ketones with Chalcones: Approach to Functionalized Six-Membered-Ring Carbocycles

      Lu Yu, Qingjing Yang and Pengfei Li

      Article first published online: 6 OCT 2014 | DOI: 10.1002/ejoc.201403075

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      Domino reactions between γ-nitro ketones and α,β-unsaturated ketones using a phase-transfer catalyst were developed. In the presence of Bu4NI and KOH, functionalized six-membered-ring carbocycles were formed in good to high yields and with excellent diastereoselectivities. This represents a new and efficient method for the construction of functionalized cyclohexane skeletons.

    3. Nitration

      Oxone®/KI-Mediated Nitration of Alkenes and Alkynes: Synthesis of Nitro- and β-Iodonitro-Substituted Alkenes

      Sornsiri Hlekhlai, Natthapol Samakkanad, Tassaporn Sawangphon, Manat Pohmakotr, Vichai Reutrakul, Darunee Soorukram, Thaworn Jaipetch and Chutima Kuhakarn

      Article first published online: 6 OCT 2014 | DOI: 10.1002/ejoc.201402750

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      Oxone® (2KHSO5·KHSO4·K2SO4) was used to promote the reactions of alkenes and alkynes with sodium nitrite (NaNO2) and potassium iodide (KI) to afford the corresponding nitro and β-iodonitro-substituted alkenes, respectively, in moderate to good yields.

  15. Short Communications

    1. Fluorochromes

      Synthesis and Glycoconjugation of an Azido-BF2–Azadipyrromethene Near-Infrared Fluorochrome

      Dan Wu, Shane Cheung, Robin Daly, Helen Burke, Eoin M. Scanlan and Donal F. O'Shea

      Article first published online: 2 OCT 2014 | DOI: 10.1002/ejoc.201402960

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      The synthesis of a water-soluble azido near-IR fluorochrome based on the BF2–azadipyrromethene fluorophore class is described. The fluorochrome can be effectively conjugated to alkyne-substituted carbohydrates by click chemistry in water at room temperature in 20 min. This azido-BF2–azadipyrromethene fluorochrome offers the potential to be a new near-IR imaging research tool for biology.

  16. Microreviews

    1. Sugar-Derived Organocatalysts

      Applications of Carbohydrate-Based Organocatalysts in Enantioselective Synthesis

      Ana Maria Faísca Phillips

      Article first published online: 2 OCT 2014 | DOI: 10.1002/ejoc.201402689

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      Carbohydrates, with their rigid backbones, large numbers of functional groups and high contents of chiral centres, are an appealing natural resource for the development of organocatalysts. They are becoming increasingly popular new tools for enantioselective synthesis, and this subject is reviewed for the period from 2009 to mid-2014.

  17. Full Papers

    1. Allylation

      Enantioselective Allylation of Selected ortho-Substituted Benzaldehydes: A Comparative Study

      Filip Hessler, Robert Betík, Aneta Kadlčíková, Roman Belle and Martin Kotora

      Article first published online: 1 OCT 2014 | DOI: 10.1002/ejoc.201403034

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      A systematic study of the allylation of variously ortho-substituted benzaldehydes under catalysis of a Lewis base (N,N-dioxides), a Lewis acid (Keck allylation), and a Brønsted acid (TRIP PA) was carried out. The highest achieved enantiomeric excess was 92 % ee.

    2. Chemoselective Alkylation

      Lithium–Titanium Exchange of Tertiary α-Sulfonyl Carbanions: Synthesis, Structure, Dynamics and Reactivity of Bis(1-sulfonylalkyl)titaniums

      Thomas Heß, Gerhard Raabe and Hans-Joachim Gais

      Article first published online: 1 OCT 2014 | DOI: 10.1002/ejoc.201402896

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      Li–Ti exchange of the lithium salts of cyclic and tertiary acyclic α-sulfonyl carbanions affords bis(1-sulfonylalkyl)titaniums. These compounds are non-fluxional, show no tendency for β-H elimination at room temperature, and display chemoselectivity towards electrophiles. In the crystal, the bis(1-sulfonylalkyl)titaniums adopt distorted octahedral asymmetric structures with hexacoordinate Ti atoms.

    3. Chemoselective Cross-Coupling

      Chemoselective Synthesis of 4,5-Diarylpyrrolo[2,3-d]pyrimidines (6,7-Diaryl-7-deazapurines) by Consecutive Suzuki and Liebeskind–Srogl Cross-Couplings

      Matouš Krömer, Martin Klečka, Lenka Slavětínská, Blanka Klepetářová and Michal Hocek

      Article first published online: 1 OCT 2014 | DOI: 10.1002/ejoc.201402882

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      A fully orthogonal sequence of the Suzuki coupling followed by Liebeskind–Srogl coupling starting from 7-benzyl-protected 4-(phenylsulfanyl)-5-iodopyrrolo[2,3-d]pyrimidine gave chemoselectively 4,5-diarylpyrrolo[2,3-d]pyrimidine derivatives.

    4. Marine Natural Products

      Total Synthesis of Micromide: a Marine Natural Product

      Jianrong Han, Jingtang Lian, Xia Tian, Shengwei Zhou, Xiaoli Zhen and Shouxin Liu

      Article first published online: 30 SEP 2014 | DOI: 10.1002/ejoc.201402977

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      An efficient method to synthesize micromide, a natural product with anti-solid-tumor activity, is described. Our strategy involved the synthesis of N-nosyl-protected amino acids and their N-methylation using iodomethane. The hindered oligopeptides containing N-methyl-substituted amino acids were synthesized in excellent yields and high purities.

    5. Natural Products

      Synthesis and Biological Studies of a Triazole Analogue of Resorcylic Acid Lactone LL-Z1640-2

      Wendy Y. L. Goh, Christina L. L. Chai and Anqi Chen

      Article first published online: 30 SEP 2014 | DOI: 10.1002/ejoc.201403010

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      A highly convergent and concise synthesis of a triazole analogue of resorcylic acid lactone natural product LL-Z1640-2 has been achieved from easily accessible starting materials. Biological evaluation confirmed that the enone system of the natural product is critical for its activity. Good activity against MNK2 kinase, which is an emerging target for cancer chemotherapy, was observed.

  18. Short Communications

    1. C–P Bond Formation

      Carbon–Phosphorus Bond Formation by Enantioselective Palladium-Catalyzed Allylation of Diphenylphosphine Oxide

      Liang Zhang, Wei Liu and Xiaoming Zhao

      Article first published online: 30 SEP 2014 | DOI: 10.1002/ejoc.201403024

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      The Pd-catalyzed asymmetric allylation of diphenylphosphine oxide to form P-allylated products in yields up to 95 % with 97 % ee is described. Pd-catalyzed allylation of (E)-methyl allyl carbonates with diisopropyl phosphonate is accomplished, which regioselectively gives linear P-allylated products in 65–95 % yields; BINAP = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl.

  19. Full Papers

    1. Fluorinated Compounds

      Access to Difluoromethylated Alkynes through the Castro–Stephens Reaction

      Tatiana Besset, Thomas Poisson and Xavier Pannecoucke

      Article first published online: 30 SEP 2014 | DOI: 10.1002/ejoc.201402937

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      Based on a Castro–Stephens transformation, a coupling reaction between copper acetylides and inexpensive and readily available BrCF2CO2Et was developed. The approach offers straightforward access to a panel of synthetically valuable aryl, heteroaryl and alkyl difluoromethylated alkynes.

    2. Synthesis of Retinals

      Short, Convergent Synthesis of Locked Retinals

      Michal S. Andrä and C. Christoph Tzschucke

      Article first published online: 29 SEP 2014 | DOI: 10.1002/ejoc.201403006

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      A short synthesis of two configurationally locked retinals is reported, that relies on alkoxycarbonylation and Wittig olefination as key steps. The convergent reaction sequence differs from previous syntheses of comparable locked retinoids by a common preparative approach of the two carbonyl precursors for the Wittig olefination and by a useful total yield of both retinals.

    3. C–H Bond Activation

      Rhodium-Catalyzed Oxidative Perfluoroalkenylation by Carbonyl Group Directed C–H Bond Activation

      Subban Kathiravan and Ian A. Nicholls

      Article first published online: 29 SEP 2014 | DOI: 10.1002/ejoc.201402904

      Thumbnail image of graphical abstract

      The synthesis of perfluoroalkenylated carbonyl derivatives was achieved by using a RhIII-catalyzed C–H bond activation reaction that was assisted by a weakly coordinating carbonyl group to couple perfluorinated acrylates and acetophenone derivatives. The reaction is compatible under aerobic conditions, has a broad substrate scope, and gives access to highly fluorinated acrylate derivatives.

  20. Short Communications

    1. Oxidative Coupling

      Copper-Catalyzed Formation of C–O Bonds by Oxidative Coupling of Benzylic Alcohols with Ethers

      Quan Wang, Haoran Geng, Wen Chai, Xiaojun Zeng, Min Xu, Cheng Zhu, Renzhong Fu and Rongxin Yuan

      Article first published online: 29 SEP 2014 | DOI: 10.1002/ejoc.201402885

      Thumbnail image of graphical abstract

      The copper-catalyzed formation of C–O bonds by oxidative coupling of benzylic alcohols with ethers is realized in open air. A series of α-acyloxy ethers were obtained in good yields with aqueous tert-butyl hydroperoxide as the oxidant.

  21. Full Papers

    1. Selective Cyclization

      Transition-Metal-Catalyzed Selective Cyclization Strategy to 2-Substituted Benzofurans and Indoles en Route to the Oxa Analogues of Isocryptolepine

      Satrajit Indu, Parthasarathi Subramanian and Krishna P. Kaliappan

      Article first published online: 29 SEP 2014 | DOI: 10.1002/ejoc.201402869

      Thumbnail image of graphical abstract

      We have described a selective cyclization strategy to prepare 2-substituted benzofurans and indoles from similar starting materials. Substrates with free –NH2 groups, which are traditionally reluctant to undergo Sonogashira coupling reactions, afforded good yields of product. The resulting benzofurans were further employed in the preparation of oxa analogues isocryptolepine.

    2. Asymmetric Catalysis

      Copper-Catalyzed Asymmetric Addition to Isatins to give 3-Hydroxy-2-oxindoles by C–H Activation

      Tao Deng, Hongjun Wang and Chun Cai

      Article first published online: 29 SEP 2014 | DOI: 10.1002/ejoc.201402852

      Thumbnail image of graphical abstract

      A copper-catalyzed asymmetric addition to isatins to give 3-hydroxy-2-oxindoles by C–H activation with a fluorous bis(oxazoline) as ligand is presented. The fluorous ligand can be easily recovered and reused at least three times without significant loss in its activity.

    3. Asymmetric Mannich Reaction of Malonates with Aldimines Using YbIII-Pybox Complexes Supported on Self-Assembled Organic–Inorganic Hybrid Silica with an Imidazolium Framework

      Babak Karimi, Ehsan Jafari and Dieter Enders

      Article first published online: 29 SEP 2014 | DOI: 10.1002/ejoc.201402713

      Thumbnail image of graphical abstract

      Yb(OTf)3/iPr-pybox immobilized on a self-assembled organic–inorganic hybrid silica with ionic liquid phase (SAILP) behaves as a very efficient and recyclable heterogeneous catalyst in the enantioselective Mannich reaction of malonate esters with N-Boc aldimines to afford the corresponding products in good yields and enantioselectivities

    4. Diarylethenes

      Enhanced Photochemical Sensitivity in Photochromic Diarylethenes Based on a Benzothiophene/Thiophene Nonsymmetrical Structure

      Olivier Galangau, Yuka Kimura, Rui Kanazawa, Takuya Nakashima and Tsuyoshi Kawai

      Article first published online: 29 SEP 2014 | DOI: 10.1002/ejoc.201402774

      Thumbnail image of graphical abstract

      We provide evidence (VTNMR, X-ray data, DFT simulations) that a standard nonsymmetric diarylethene containing a benzothiophene unit achieves high ring cyclization quantum yield by means of favorable intramolecular interactions (CH–π, H–F bonding or steric hindrance).

    5. Luminescent Borate Complexes

      Solution- and Solid-State Luminescent Borate Complexes Based on a Substituted π-Conjugated 2-(6′-Hydroxy-5′-benzofuryl) Scaffold

      Karima Benelhadj, Julien Massue, Pascal Retailleau, Siwar Chibani, Boris Le Guennic, Denis Jacquemin, Raymond Ziessel and Gilles Ulrich

      Article first published online: 29 SEP 2014 | DOI: 10.1002/ejoc.201402806

      Thumbnail image of graphical abstract

      A series of borate complexes based on an original 2-(6′-hydroxy-5′-benzofuryl) scaffold have been synthesized that are highly luminescent both in solution and in the solid state. Depending on their substitution, they exhibit either a strong internal charge transfer leading to pronounced solvatochromism or singlet emission. Their emission spans the whole visible range with quantum yields of up to 87 %.

  22. Short Communications

    1. Oxidative Arylation

      Oxidative (Cross-)Coupling Reactions Mediated by C–H Activation of Thiophene Derivatives by Using Molybdenum(V) Reagents

      Moritz Schubert, Simon Trosien, Lara Schulz, Carolin Brandscheid, Dieter Schollmeyer and Siegfried R. Waldvogel

      Article first published online: 26 SEP 2014 | DOI: 10.1002/ejoc.201403188

      Thumbnail image of graphical abstract

      The unique performance of MoCl5 gives rise to a variety of complex structures involving the thiophene motif. The oxidative coupling is performed in the 2,3-positions of the thiophene moiety. In this approach, the first cross-coupling reactions by using MoCl5 are established.

  23. Full Papers

    1. Nitrogen Heterocycles

      Modular Access to Highly Functionalised Tetrahydroquinolines

      Franca M. Cordero, Bhushan B. Khairnar and Alberto Brandi

      Article first published online: 26 SEP 2014 | DOI: 10.1002/ejoc.201403025

      Thumbnail image of graphical abstract

      Highly functionalised tetrahydroquinolines can be obtained by a modular approach consisting of a nitrone 1,3-dipolar cycloaddition to 2-bromostyrene followed by isoxazolidine N–O cleavage and copper-catalysed aromatic N-substitution/cyclisation. A 1,2,3,4-tetrahydro-1,8-naphthyridine was obtained in the same way.

  24. Short Communications

    1. Domino Reactions

      Synthesis of Furans through Silver-Catalyzed Propargyl–Claisen Rearrangement Followed by Cyclocondensation

      Adeline Palisse and Stefan F. Kirsch

      Article first published online: 26 SEP 2014 | DOI: 10.1002/ejoc.201402983

      Thumbnail image of graphical abstract

      Propargyl vinyl ethers with a free hydroxy group are converted into highly substituted furans by using AgBF4 through a sequence consisting of [3,3] sigmatropic rearrangement and cyclocondensation. This domino reaction allows the synthesis of various tri- and tetrasubstituted furan products.

    2. Reaction Mechanisms

      Insight into the Mechanisms of the Multicomponent Ugi and Ugi–Smiles Reactions by ESI-MS(/MS)

      Claudio Iacobucci, Samantha Reale, Jean-François Gal and Francesco De Angelis

      Article first published online: 26 SEP 2014 | DOI: 10.1002/ejoc.201403179

      Thumbnail image of graphical abstract

      All key intermediates in the Ugi and Ugi–Smiles reactions are intercepted and structurally characterized by ESI-MS/MS without the assistance of charged hooks. In particular, the coexistence of the two isomeric species of the Mumm rearrangement in the gas phase is elucidated. The reaction pathway originally hypothesized by Ugi is thus confirmed.

    3. Cooperative Catalysis

      Brønsted Acid/Lewis Acid Cooperatively Catalyzed Addition of Diazoesters to 2H-Chromene Acetals

      Yi Luan, Yue Qi, Hongyi Gao, Qianqian Ma and Scott E. Schaus

      Article first published online: 25 SEP 2014 | DOI: 10.1002/ejoc.201403043

      Thumbnail image of graphical abstract

      A Brønsted acid/Lewis acid dual catalyst system is developed to promote efficient C–C bond formation between oxocarbenium precursors derived from chromene acetals and ethyl diazoacetate. The reaction proceeds under mild conditions and is tolerant of functionalized 2H-chromenes and isochromene acetals. An asymmetric variant of diazoacetate addition towards 2H-chromene acetals is also described.

    4. Alkenylation

      Ruthenium-Catalyzed Switchable N–H/C–H Alkenylation of 6-Phenyl(dihydro)pyridazinones with Alkynes

      Wei Wang, Lei Liang, Fengrong Xu, Wenjie Huang, Yan Niu, Qi Sun and Ping Xu

      Article first published online: 25 SEP 2014 | DOI: 10.1002/ejoc.201402986

      Thumbnail image of graphical abstract

      A Ru-catalyzed switchable N–H/C–H alkenylation reaction of 6-phenyl(dihydro)pyridazin-3(2H)-ones triggered by a N2/O2 atmosphere is developed. To achieve switchable modification of the two important sites of the widely used pharmacophore, a simple and efficient procedure is utilized that affords excellent activity, high selectivity, and good tolerance of a wide range of functional groups.

  25. Full Papers

    1. Amino Acid Synthesis

      Practical Syntheses of Both Enantiomers of the Conformationally Restricted GABA Analogue cis-(2-Aminocyclobutyl)acetic Acid

      Hawraà Awada, Sylvie Robin, Régis Guillot, Ogaritte Yazbeck, Daoud Naoufal, Nada Jaber, Ali Hachem and David J. Aitken

      Article first published online: 25 SEP 2014 | DOI: 10.1002/ejoc.201402676

      Thumbnail image of graphical abstract

      Two complementary construction approaches ― homologation of a β-amino acid and atom-efficient photocyclization of an azepin-2-one ― followed by chiral resolution provide access to both enantiomers of this cyclobutane-restricted GABA analogue.

  26. Short Communications

    1. Natural Products

      High-Yielding Total Synthesis of Sexually Deceptive Chiloglottones and Antimicrobial Dialkylresorcinols through an Organocatalytic Reductive Coupling Reaction

      Rudrakshula Madhavachary and Dhevalapally B. Ramachary

      Article first published online: 24 SEP 2014 | DOI: 10.1002/ejoc.201403128

      Thumbnail image of graphical abstract

      Sexually deceptive chiloglottones, antimicrobial dialkylresorcinols, and their many analogues are synthesized in very good yields in a sequential two-pot manner by using an “organocatalytic reductive coupling reaction” as the key step.

  27. Full Papers

    1. Heterocyclic Rearrangements

      The Boulton–Katritzky Reaction: A Kinetic Study of the Effect of 5-Nitrogen Substituents on the Rearrangement of Some (Z)-Phenylhydrazones of 3-Benzoyl-1,2,4-oxadiazoles

      Vincenzo Frenna, Antonio Palumbo Piccionello, Barbara Cosimelli, Franco Ghelfi and Domenico Spinelli

      Article first published online: 24 SEP 2014 | DOI: 10.1002/ejoc.201402569

      Thumbnail image of graphical abstract

      The kinetics of the Buolton–Katritzky reaction of nitrogen-substituted phenylhydrazones of 3-benzoyl-1,2,4-oxadiazole to give the relevant triazoles have been examined in a wide range of pS+. The effect of substituents on three different pathways was elucidated.

    2. Anion Recognition

      Sulfate Encapsulation in Supramolecular Structures from L-Asparagine-Derived 2,5-Diketopiperazine Scaffolds: Anion Binding

      Santhosh Reddy Naini, Roger A. Lalancette, Olga Gorlova, Kallaganti V. S. Ramakrishna, Jhillu Singh Yadav and Subramania Ranganathan

      Article first published online: 24 SEP 2014 | DOI: 10.1002/ejoc.201402610

      Thumbnail image of graphical abstract

      We report a new sulfate receptor, anchored onto 2,5-diketopiperazine units, which results in the formation of two types of supramolecules; one in which the sulfate ion guest fits snugly into extended cavities and the other in which the guest is sandwiched between layers. In each case, the anion is held by six hydrogen bonds from the host. Job plots and association constants were calculated.

    3. Cross-Coupling

      A Versatile and Efficient Palladium–meta-Terarylphosphine Catalyst for the Copper-Free Sonogashira Coupling of (Hetero-)Aryl Chlorides and Alkynes

      Yong Yang, Xinying Chew, Charles W. Johannes, Edward G. Robins, Howard Jong and Yee Hwee Lim

      Article first published online: 24 SEP 2014 | DOI: 10.1002/ejoc.201402699

      Thumbnail image of graphical abstract

      A protocol is devised for the cross-coupling of electron-rich aryl chlorides with terminal alkynes by using Pd–Cy*Phine, which is a highly active in situ catalyst containing a novel meta-terarylphosphine ligand. Excellent yields are achieved with minimal generation of byproducts. The versatility of this reaction is demonstrated by its tolerance of a range of unprotected functional groups.

    4. Alkaloids

      A Glycal Approach to the Synthesis of Steviamine Analogues

      Venkatesan Santhanam and Namakkal G. Ramesh

      Article first published online: 24 SEP 2014 | DOI: 10.1002/ejoc.201402943

      Thumbnail image of graphical abstract

      We present the synthesis of two new diastereomers of steviamine, an indolizidine alkaloid isolated from Stevia rebaudiana.

    5. Heterocyclic Chemistry

      One-Pot Multiple Lithiation Processes of Fused Heterocycles

      Adeline Jasselin-Hinschberger, Corinne Comoy and Yves Fort

      Article first published online: 24 SEP 2014 | DOI: 10.1002/ejoc.201402967

      Thumbnail image of graphical abstract

      An efficient one-pot process for the functionalization of aza-heterocycles at multiple sites was developed that involves two or three successive regioselective lithiation/electrophile trapping stages and allows for the preparation of highly substituted furo[3,2-b]pyridines.

  28. Short Communications

    1. Arylation

      Cesium Carbonate Promoted Direct Arylation of Hydroxylamines and Oximes with Diaryliodonium Salts

      Yang Yang, Xunshen Wu, Jianwei Han, Song Mao, Xiaofei Qian and Limin Wang

      Article first published online: 24 SEP 2014 | DOI: 10.1002/ejoc.201402920

      Thumbnail image of graphical abstract

      An efficient method for the transition-metal-free arylation of hydroxylamines and oximes with diaryliodonium salts is described. A range of N-arylhydroxylamines with various aryl substituents that would be useful in the preparation of valuable chemicals are obtained in good to excellent yields. Cbz = benzyloxycarbonyl, Boc = tert-butoxycarbonyl, TBDMS = tert-butyldimethylsilyl, TBDPS = tert-butyldiphenylsilyl, Bn = benzyl, Tf = trifluoromethylsulfonyl.

    2. Domino Reactions

      Synthesis of 2-Alkylideneisochromans by Cyclocarbonylative Sonogashira Reactions

      Laura Antonella Aronica, Luca Giannotti, Stefano Giuntini and Anna Maria Caporusso

      Article first published online: 24 SEP 2014 | DOI: 10.1002/ejoc.201402979

      Thumbnail image of graphical abstract

      An atom-economic, palladium-catalyzed carbonylative Sonogashira reaction/cyclisation sequence is used for the preparation of 2-alkylideneisochromans in high yields with high stereoselectivity.

    3. Organocatalysis

      First Microwave-Assisted Catalytic Wittig Reaction

      Thomas Werner, Marcel Hoffmann and Sunetra Deshmukh

      Article first published online: 24 SEP 2014 | DOI: 10.1002/ejoc.201403113

      Thumbnail image of graphical abstract

      The first catalytic Wittig reaction under microwave irradiation is reported. Readily available tributylphosphine oxide acts as the precatalyst. Under optimized conditions, a variety of aromatic, aliphatic, and heteroaromatic aldehydes could be converted efficiently. Moreover, one example of the first asymmetric version under these conditions is enclosed.

  29. Full Papers

    1. Iodine-Mediated Oxidation

      Iodine-Mediated Oxidation of Ynamides: A Facile Access to N-Monosubstituted α-Ketoamides and α-Ketoimides

      Hai Huang, Guangke He, Xiaolin Zhu, Xiaodong Jin, Shineng Qiu and Hongjun Zhu

      Article first published online: 24 SEP 2014 | DOI: 10.1002/ejoc.201402538

      Thumbnail image of graphical abstract

      An iodine-mediated aerobic oxidation reaction for ynamides has been developed. This approach provides the desired products in moderate to excellent yields, and the reaction has good functional group tolerance, thereby enabling access to N-monosubstituted α-ketoamides and α-ketoimides. Iodine, which is a mild Lewis acid, serves an important role in this oxidative process.

    2. Selenium Heterocycles

      Synthesis of 2-Substituted 1,3-Benzoselenazoles from Carboxylic Acids Promoted by Tributylphosphine

      Cátia Schwartz Radatz, Daniel S. Rampon, Renata A. Balaguez, Diego Alves and Paulo Henrique Schneider

      Article first published online: 22 SEP 2014 | DOI: 10.1002/ejoc.201402808

      Thumbnail image of graphical abstract

      A metal-free synthesis of 2-substituted 1,3-benzoselenazoles by the reaction of bis(2-aminophenyl)diselenide with carboxylic acids, promoted by tributylphosphine is reported. For the first time, 2-alkyl-1,3-benzoselenazoles could be obtained from aliphatic carboxylic acids and thiazolidine-4-carboxylic acid in high chemical yields. Microwave irradiation reduced the reaction time.

    3. Amino-Substituted Carbasugars

      Synthesis and α-Glucosidase and α-Amylase Inhibitory Activity Evaluation of Azido- and Aminocyclitols

      Gökay Aydin, Khamis Ally, Fatih Aktaş, Ertan Şahin, Arif Baran and Metin Balci

      Article first published online: 22 SEP 2014 | DOI: 10.1002/ejoc.201402762

      Thumbnail image of graphical abstract

      Aminocyclitols are found in many natural products with remarkable biological activities. The synthesis of various amino-substituted carbasugars and their inhibitory effects against α-glucosidase and α-amylase are discussed.

    4. Dipyrromethanes

      Reactivity of Dipyrromethanes towards Azoalkenes: Synthesis of Functionalized Dipyrromethanes, Calix[4]pyrroles, and Bilanes

      Susana M. M. Lopes, Américo Lemos and Teresa M. V. D. Pinho e Melo

      Article first published online: 19 SEP 2014 | DOI: 10.1002/ejoc.201402944

      Thumbnail image of graphical abstract

      The hetero-Diels–Alder reaction of dipyrromethanes and azoalkenes was explored as the key step for the synthesis of new dipyrromethanes, calix[4]pyrroles, and bilanes.

    5. Supramolecular Chemistry

      1,8-Dioxyanthracene-Derived Crown Ethers: Synthesis, Complexation with Paraquat and Assembly of a Tetracationic Cyclophane-Crown Ether Based [2]Catenane

      Bo Tang, Hong-Mei Yang, Wen-Jing Hu, Ming-Liang Ma, Yahu A. Liu, Jiu-Sheng Li, Biao Jiang and Ke Wen

      Article first published online: 19 SEP 2014 | DOI: 10.1002/ejoc.201402876

      Thumbnail image of graphical abstract

      Sandwich and crescent conformations were adopted by bis-1,8-dioxyanthracene-based crown ethers upon complexation with methyl viologen dication (see Scheme). The structure of the complexes are highly dependent on the length of polyether chains of the crown ethers.

    6. Natural Products

      Diversity-Oriented Synthesis of Calothrixins and Ellipticines

      Dattatraya H. Dethe and Ganesh M. Murhade

      Article first published online: 19 SEP 2014 | DOI: 10.1002/ejoc.201402837

      Thumbnail image of graphical abstract

      The divergent synthesis of calothrixins and ellipticines has been accomplished by utilising the one-pot formation of o-diacylarenes as a key intermediate through rearrangement of o-hydroxy ketone monoacyl hydrazones by lead tetraacetate mediated oxidation.

    7. Asymmetric Transfer Hydrogenation

      Microwave-Enhanced Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)imines

      Óscar Pablo, David Guijarro and Miguel Yus

      Article first published online: 18 SEP 2014 | DOI: 10.1002/ejoc.201402884

      Thumbnail image of graphical abstract

      Microwave irradiation promotes the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)imines in 2-propanol catalysed by a ruthenium complex bearing an achiral β-amino alcohol as ligand. After desulfinylation, α-branched primary amines containing aromatic, heteroaromatic and aliphatic substituents are obtained in excellent yields and with enantiomeric excesses of up to 96 %.

  30. Microreviews

    1. Manipulating Peptide Structures

      Heterogeneous Foldamers from Aliphatic–Aromatic Amino Acid Building Blocks: Current Trends and Future Prospects

      Roshna V. Nair, Kuruppanthara N. Vijayadas, Arup Roy and Gangadhar J. Sanjayan

      Article first published online: 18 SEP 2014 | DOI: 10.1002/ejoc.201402877

      Thumbnail image of graphical abstract

      This review is an effort to cover this rapidly developing field of foldamer science involving aliphatic-aromatic conjugate building blocks and to envisage its future perspectives.

  31. Full Papers

    1. Total Synthesis

      Synthesis of the Sesquiterpenes Albicanol, Drimanol, and Drimanic Acid, and the Marine Sesquiterpene Hydroquinone Deoxyspongiaquinol

      Matthias Göhl and Karlheinz Seifert

      Article first published online: 18 SEP 2014 | DOI: 10.1002/ejoc.201402873

      Thumbnail image of graphical abstract

      The valuable building blocks in the synthesis of various meroterpenes (+)-albicanyl acetate, (+)-albicanol, (+)-drimanol, and (+)-drimanic acid were synthesized through a TiIII-mediated radical cyclization cascade starting from all-trans-farnesol. (+)-Drimanic acid was transformed into the marine sesquiterpene hydroquinone deoxyspongiaquinol. Thus, five natural products were synthesized.

    2. Base-Initiated Rearrangement

      Synthesis of 1,2-Diols and Their Base-Initiated Rearrangement to Butyrolactones

      Mauro Moliterno, Cristiana Margarita, Silvia Panarello, Riccardo Salvio and Marco Bella

      Article first published online: 17 SEP 2014 | DOI: 10.1002/ejoc.201402853

      Thumbnail image of graphical abstract

      Unsaturated 3-hydroxybutyrolactones (isotetronic acids) have been prepared by a novel rearrangement of 1,2-diols involving an unusual alkyl shift. A possible mechanism is described with the aid of DFT calculations.

    3. Lewis Acid Promoted Cyclization

      Six-Membered Ring Formation from Lewis Acid Promoted Reactions of 2-Substituted 2-Alkenyl Amides and Esters of Ethenetricarboxylate

      Shoko Yamazaki, Kohta Ueda, Yugo Fukushima, Akiya Ogawa and Kiyomi Kakiuchi

      Article first published online: 17 SEP 2014 | DOI: 10.1002/ejoc.201402637

      Thumbnail image of graphical abstract

      The Lewis acid promoted reactions of 2-substituted 2-propenyl amides and allenyl esters of ethenetricarboxylate gave six-membered-ring heterocycles as the major products. In the reactions of the 2-substituted 2-propenyl amides, elimination products were obtained selectively instead of the substitution products.

    4. Asymmetric Sulfinylation

      DMAP-Catalysed Sulfinylation of Diacetone-D-Glucose: Improved Method for the Synthesis of Enantiopure tert-Butyl Sulfoxides and tert-Butanesulfinamides

      Ahmed Chelouan, Rocío Recio, Ana Alcudia, Noureddine Khiar and Inmaculada Fernández

      Article first published online: 16 SEP 2014 | DOI: 10.1002/ejoc.201402673

      Thumbnail image of graphical abstract

      An improved method for the tert-butanesulfinylation of diacetone glucose with tert-butanesulfinyl chloride is reported. The resulting (RS)-DAG sulfinate ester 2RS is an excellent C- and N-sulfinylating agent that can be used for the synthesis of relevant enantiopure sulfoxides and (SS)-tert-butanesulfinamides.

    5. Cross-Coupling Reactions

      Suzuki–Miyaura Coupling of Aryl Chlorides with Arylboronic Acids Using the Morpholine–NiCl2 Catalyst System

      Taichi Abe, Takashi Mino, Kohei Watanabe and Masami Sakamoto

      Article first published online: 16 SEP 2014 | DOI: 10.1002/ejoc.201402881

      Thumbnail image of graphical abstract

      We report morpholine–NiCl2 as a new catalyst system for the Suzuki–Miyaura coupling of aryl chlorides with aryl- or alkenylboronic acids to give biaryl compounds. This catalyst system is easy to apply on a large scale because of its easy preparation and the use of inexpensive reagents, and has broad substrate scope. Analysis of the residual nickel showed only 9.7 ppm remaining after work-up.

    6. Reaction Mechanisms

      Addition–Elimination versus Direct Substitution Mechanisms for Arene Chlorination

      Boris Galabov, Gergana Koleva, Jing Kong, Henry F. Schaefer III and Paul v. R. Schleyer

      Article first published online: 15 SEP 2014 | DOI: 10.1002/ejoc.201402765

      Thumbnail image of graphical abstract

      The present comprehensive DFT computational exploration of aromatic chlorination predicts that the barriers for the addition of Cl2 to benzene, toluene and naphthalene catalyzed by HCl in the gas phase and in simulated CCl4 solution can be even lower than the barriers for direct substitution. Moreover, substitution products also can arise from stepwise Cl2 addition/HCl elimination routes.

    7. Prins Reactions

      Toward Pyridine–Heterocycle Patterns through Prins and Aza-Prins Cyclisations: Application to a Short Synthesis of (±)-Anabasine

      Olivier Colin, Christine Greck, Damien Prim and Christine Thomassigny

      Article first published online: 15 SEP 2014 | DOI: 10.1002/ejoc.201402971

      Thumbnail image of graphical abstract

      The (aza)-Prins cyclisation has been applied to several pyridine carbaldehydes, opening the way to an easy access to bisheterocycles. The method was effective for the synthesis of anabasine in two steps.

    8. Fluorinated Oligoporphyrins

      Synthesis of Highly Fluoroalkyl-Functionalized Oligoporphyrin Systems

      Lukas Felix, Ugur Sezer, Markus Arndt and Marcel Mayor

      Article first published online: 12 SEP 2014 | DOI: 10.1002/ejoc.201402816

      Thumbnail image of graphical abstract

      Massive but volatile molecules have been obtained by functionalizing the periphery of oligoporphyrins with highly fluorinated alkyl chains. The statistical nature of the reaction gives libraries consisting of molecules with well-defined masses but small structural diversity. Laser desorption and post-ionization studies demonstrated the potential of these libraries as sources of heavy particles.

    9. Protecting Groups

      Efficient Transfer of Chelating Amides into Different Types of Esters and Lactones

      Uwe Jakob, Stephan Mundinger and Willi Bannwarth

      Article first published online: 12 SEP 2014 | DOI: 10.1002/ejoc.201402843

      Thumbnail image of graphical abstract

      Due to their high resonance energy, amides are generally very stable towards solvolysis. However, bispicolylamides can be activated for alcoholysis by an unusual metal coordination involving the electron pair of the amide nitrogen. Herein, we widened the scope of the reaction by transforming the amides into a range of esters and lactones.

  32. Microreviews

    1. Aminoglycosides

      2-Nitroglycals: Versatile Building Blocks for the Synthesis of 2-Aminoglycosides

      Thierry Delaunay, Thomas Poisson, Philippe Jubault and Xavier Pannecoucke

      Article first published online: 12 SEP 2014 | DOI: 10.1002/ejoc.201402805

      Thumbnail image of graphical abstract

      Nitration of glycals gives access to the versatile 2-nitroglycal derivatives. These key building blocks are used for the synthesis of potent biologically active compounds. This review highlights the chemistry of 2-nitroglycals and their applications.

    2. Vicinal Quaternary Stereocenters

      The Nazarov Cyclization: A Valuable Method to Synthesize Fully Substituted Carbon Stereocenters

      Donald R. Wenz and Javier Read de Alaniz

      Article first published online: 9 SEP 2014 | DOI: 10.1002/ejoc.201402825

      Thumbnail image of graphical abstract

      We describe three general approaches to the formation of fully substituted quaternary carbon stereocenters by means of the Nazarov cyclization.

  33. Full Papers

    1. Peroxides

      Six Peroxide Groups in One Molecule – Synthesis of Nine-Membered Bicyclic Silyl Peroxides

      Ashot V. Arzumanyan, Alexander O. Terent'ev, Roman A. Novikov, Valentin G. Lakhtin, Vladimir V. Chernyshev, Andrew N. Fitch and Gennady I. Nikishin

      Article first published online: 4 SEP 2014 | DOI: 10.1002/ejoc.201402895

      Thumbnail image of graphical abstract

      Compounds containing two nine-membered peroxide rings bridged by an ethane, ethene, or ethyne group are synthesized. Each ring is formed by the replacement of two geminal chlorine atoms at the silicon atom with the hydroperoxide groups of one peroxide molecule. The peroxides are isolated by crystallization or silica gel filtration; unexpectedly, all of these compounds are extremely explosive.

    2. Chelators for Bioconjugation

      Efficient Synthesis of 1,4,7-Triazacyclononane and 1,4,7-Triazacyclononane-Based Bifunctional Chelators for Bioconjugation

      Pauline Désogère, Yoann Rousselin, Sophie Poty, Claire Bernhard, Christine Goze, Frédéric Boschetti and Franck Denat

      Article first published online: 4 SEP 2014 | DOI: 10.1002/ejoc.201402708

      Thumbnail image of graphical abstract

      A new synthesis of 1,4,7-triazacyclononane and its N-functionalized derivatives is described. This powerful approach outperforms previous synthetic methods due to the use of an aminal intermediate. The method can be extended to the synthesis of valuable C-functionalized building blocks, giving access to a wide range of new bifunctional chelating agents, such as the p-NCS-Bz-MA-NOTA chelator.

  34. Microreviews

    1. Complementary Recognition Sites

      Supramolecular Control of Reactivity and Catalysis – Effective Molarities of Recognition-Mediated Bimolecular Reactions

      Stefano Di Stefano, Roberta Cacciapaglia and Luigi Mandolini

      Article first published online: 26 AUG 2014 | DOI: 10.1002/ejoc.201402690

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      Effective molarities (EM) of intramolecular reactions in 1:1 supramolecular complexes are critically surveyed and analyzed in terms of entropy and strain.

    2. Solar Cell Photosensitizers

      Multi-Branched Multi-Anchoring Metal-Free Dyes for Dye-Sensitized Solar Cells

      Norberto Manfredi, Bianca Cecconi and Alessandro Abbotto

      Article first published online: 1 AUG 2014 | DOI: 10.1002/ejoc.201402422

      Thumbnail image of graphical abstract

      Multi-branched multi-anchoring organic dyes represent a recent new class of metal-free photosensitizers for dye-sensitized solar cells of increasing interest. The article describes design strategies, synthetic routes and optical and photovoltaic properties. The multi-branched geometry is able to induce unique features that in turn give rise to relevant photovoltaic properties.

    3. Hydroamination

      Efficient Anti-Markovnikov-Selective Catalysts for Intermolecular Alkyne Hydroamination: Recent Advances and Synthetic Applications

      Jacky C. -H. Yim and Laurel L. Schafer

      Article first published online: 28 JUL 2014 | DOI: 10.1002/ejoc.201402300

      Thumbnail image of graphical abstract

      Hydroamination, the catalytic addition of an N–H bond across a C–C unsaturation site, is a 100 % atom-economical route for the construction of nitrogen-containing small molecules. However, regioselectivity is a great challenge for this reaction. This Microreview focuses on recent advances and highlights some synthetic applications of anti-Markovnikov-selective intermolecular alkyne hydroamination.

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